1. Field of the Invention
The field of this invention is use of a characteristic electrical signal to identify the location of milk duct orifices on mammalian breast nipples for purposes including accessing one or more of the milk ducts.
Analysis of ductal secretions from human breasts has been used to diagnose biological conditions of the breast ducts (1-4; see list of references hereinafter). The human nipple has from 6 to 12 ducts, and most of these studies pooled secretions or nipple aspirate fluid (NAF) for the analysis. Thus, the secretions of an individual duct are not identified in these studies. More recently, breast duct access has been incorporated into ductal fluid analyses and study protocols (5-7). Various methods have been employed in order to identify the breast ducts for purposes including duct fluid analysis (8-15). Additionally, breast ducts have been accessed by ductscope (15, 16). Ductal cannulation is proposed for delivery of agents (WO 97/05898 and (20)). Ductography, or mammary duct contrast examination, involves cannulation and injection of a ductal orifice (17-19), a process that is generally painless and devoid of complications (20).
Ductal access is also required for performing lavage procedures on a milk duct to deliver an agent and/or to retrieve cells from the duct for analysis as described in co-pending and co-owned or licensed applications including Ser. No. 09/067,661; 09/301,058; PCT US99/09141; 60/122,076; 09/313,463; 60/143,359; and application Ser. Nos. 09/473,510, filed Dec. 28, 1999, all incorporated by reference in their entirety. The challenge for the procedure can be finding a duct, or multiple ducts, for access.
It would therefore be desirable to provide improved methods, devices, and kits for accessing breast ducts. More particularly, it would be desirable to provide for the improved detection and identification of individual ductal orifices to facilitate subsequent ductal access for diagnostic and/or therapeutic purposes. Such methods, devices, and kits should be convenient and relatively simple to use, should present the patient with minimal or no discomfort, and should be highly reliable, i.e., should be able to detect all individual ductal orifices in a nipple in all or most cases. At least some of these objectives will be met by the invention described hereinafter.
2. Relevant Literature
WO 96/12439 assigned to TransScan Research & Development Corporation describes electrical impedance imaging devices having multi-element probes for providing electrical connection to tissue surfaces, particularly for detection of cancer in a live tissue, including breast tissue. U.S. Pat. No. 5,810,742 assigned also to TransScan describes an apparatus for making a tissue characterization in order to identify anomalous tissue. Faupel and Hsu, (1996) Electropotentials in the clinical assessment of breast neoplasia, Dixon eds. pp.37-44 describe measuring and analysis of skin potentials for cancer diagnosis. U.S. Pat. No. 5,678,547 to Biofield Corp. describes use of an electromagnetic field present between a reference and plurality of test points on a living organism to measure a gradient of electrical activity that occurs as a function of biological activity in order to monitor efficacy of a treatment for the disease, injury or bodily function. U.S. Pat. No. 4,291,708 and U.S. Pat. No. 4,458,694 to Yeda Research & Development Co. describe apparatus and methods for detecting tumors in living human breast tissue including instrumentalities for determining the dielectric constants of a plurality of localized regions of living human breast tissue.